Method for casting material in bars



April 1932. s. F. v. KJELLGREN 1,352,453

METHOD FOR CASTING MATERIAL IN BARS Filed May 14, 1928 dBMJM IQUWMLM Patented Apr. 5, 1932 UNITED STATES PATENT OFFIFI STEN FREDRIK VALDEMAR KJELLGZREN, F SKOGHAIQL, SWEDEN METHOD FOR CASTING MATERIAL IN BARS Application filed May 14, 1928, Serial No. 277,742, and in Sweden May 17, 1927.

As is known, some chemical products, e. g. terof course being that the lower end of caustic alkalis, are marketed in the form of the tube is also perfectly level, so as to make bars, this form of manufacture having a tight jomt, and the mould is filled with, proved practical for many purposes. The by way of example, molten hydrate of sodium cost of making the bars is, however, relat1ve- (o1: the molten mass in ql16St101'l, Of which iv high in comparison with other forms of it 1s desired to turn out bars), 1t will be 1i1ani1fact1ire because it is at present necesfound that after the bar has congealed, it is sary to make use for the same of moulds didifficult to remove it from the mould without vided lengthwise, which for every casting op the use of such force that the bar is spoiled 0 eratien have to be separated or disjointed, or damaged. If the attempt is repeated time cleaned and put together again, this work and again, without the mould between each having to be done by hand. On separating attempt being allowed to cool properly, and the moulds after finishing the casting, it hapthe temperature of the mould consequently pens that some bars that are ready, remain time and again grows higher and higher, it p 15 sticking to the separate halves, from which will be more and more difficult to remove the 05 they have to be detached with proper tools, bar until it is finally found altogether imposand even for that work manual power has sible. The cause of this must be sought in the to he resorted to. The present Working following. The molten mass, must, in order method has always, apart from large work to be capable of convenient handling, pos- 0 ing expenses, the drawback that a very unsess a certain excess temperature. On poureven product from a standpoint of size, 13 ing down into the mould, the latte absorbs usually obtained. this excess heat under a rise of temperature It should be perfectly obvious that, if and correspondingexpansion. The same mowhole moulds (i. e. moulds made in one ment the molten mass congeals, its volume is piece) could be used instead of divided ones thus greater than the inner volume of the and if such moulds were used accordlng to a t b t th commencement f th ti definite working method, the bars on cool- Th u e aft r a nge l t will th n b ingcould be loosened with facility from the that both the mould and the mass, accordmould, not only the working costs could be ing tothe drop in the temperature, must 30 reduced but also a uniform and even product contract, this double contraction nevertheless obtained, in the form of whole bars of pracon the initial temperature of'the mould havtically the same size and weight. The obing reached a certain height on account of ject of the present invention is a method by the greater heat expanding capacity of the the aid of which the aforesaid desiderata can metallic mould resulting in the mould under be obtained, and an apparatus for realizing relative shrinkage holding fast the finished the method. bar. The latter can thus not be removed An account is first given of the theoretlcal from the mould without the use of force. bases upon which a working method accord- If, however, the above train of reasonlng after a description is given by way of examwill be found. It is clearly only a question ple of one form of carrying the invention into of preventing heating with concomitant exeil'ect in order to illustrate the manner in pansion of the mould, which can be done by which these principles may be reduced to strong cooling of the outside of the mould practice. during the casting process. By this means 45 If a mould, consisting of a metal tube the result is obtained that the mass at the with thin walls and open at both ends, and moment of congealment has a volume, that is everywhere internally of absolutely the same to say, cross section which practically coindiameter, and consequently with perfectly sides with the inner volume of the mould (rer smooth inner surface, is placed upon a suitspectively the inner cross section of the able, level foundation, the premises as a matmould) before the molten mass is poured into 106 40 mg to the invention is founded, and thereis continued, a way out of the said difficulty the same. No contraction of the inner volume of the mould therefore takes place during the continued cooling of the mass. The latter in its turn diminishes, however, in volume as the temperature gradually drops. The result consequently is that the bar loosens from the inner walls of the mould and can be made to drop out by giving a slight blow to the mould.

The invention can be applied to the casting of Various kinds of substances, but is particularly suitable and adapted to fusible materials coming under some one of the groups of substances viz. metalloids, metalloid compounds, metal compounds, e. g. caustic alkalis, such as hydroxides of sodium or potassium, calcium chloride or other similar substances.

It has been proposed in the moulding of resinous materials to keep the moulds cool either by making them of massive blocks of metal or providing moulds with a water jacket in order to prevent the temperature of the moulds from rising to the temperature of adhesion ofthe resinous substance.

The present invention chiefly consists in a method for producing bars or bar-shaped bodies from fusible materials such as e. g. caustic alkalis, such as hydroxide of sodium or potassium or calcium chloride and other similar substances, consisting therein that the material in a molten condition is poured into tubular moulds of heat conducting material, for instance, metallic moulds, undivided lengthwise, which moulds during the casting process by means of a cooling agent are kept so strongly cooled that practically no expansion of the same through the influence of the supplied molten mass occurs in order that the bar owing to its contraction during the congealing and cooling obtains a smaller volume than the mould and consequently is easily loosened from the same.

By way of illustrating the invention there is shown diagrammatically in the annexed drawings a form of construction of a device for carrying into effect the method here concerned Fig. 1 shows alateral view of the device, with a portion cut away.

Fig. 2 shows the same seen from above.

In a stand 1 suitable for the purpose there is a rotatable shaft 2, which at its upper. end supports a box or tank 3 serving as a receptacle for a cooling fluid, and this box or tank according to the form of construction illustrated, has a cylindrical shape. In this box there are located vertically a number of tubes 4: serving as moulds and placed at mutually equal angular distances in a circle. The moulds or tubes 4. extend through the bottom and top of the tank 3, in such a way that their mouths lie in the same plane as the outer surfaces of the bottom and the top respectively.

These moulds or tubes cas have any cross section whatsoever suitable for the purpose, e. g. circular, rectangular or polygonal. They may have along their entire length exactly equal cross sectional area,orthe cross sectional area of each tube may preferably slightly increase continuously downwards for the purpose that in the manner described hereinafter in detail the moulded bar in question can bemore easily removed from the same. The box 3 together with the shaft 2, which according to the form of construction illustrated is tubular (see 2) is set into intermittent step by step rotating motion, and this motion for each step corresponds to the angle-distance between the centers of two adjacent moulds. This motion can be brought about with any suitable device whatsoever, e. g. by means of a reciprocating ratchet device of the nature illustrated in the drawings. This ratchet mechanism or ratchet device consists of a bar 6 having a reciprocating motion in brackets or bearings 5,-this bar 6 supporting a pawl or lug 7, which meshes with a cogged ring and arranged at the periphery of the box 3. The bar 6 is set into reciprocating motion by the actionof a rotatably arranged shaft 9, which at one end is provided with a crankpin 10, which through the agency of a linkbar 11 and a pivot 12 are articulated to the bar 6 in such a way that when the shaft 9 rotates, the bar 6 each time is set into reciproeating movement, corresponding to the peripheral length of a ratchet tooth in the cogged ring 8. When tl e bar 6 is moving towards the left (Fig. 2) the box 3 and with it also the moulds are thus made to turn slightly through the action of pawl 7 upon the corresponding tooth in the toothed ring, and turned a distance exactly corresponding to the augle-distance between two adjacent moulds. When the bar 6 thereupon moves in the opposite direction, this motion does not exert any rotary action upon the box, but the pawl 7 glides over the corresponding tooth in the ring, for which purpose the pawl 7 or the bar 6, or. the bearings or brackets supporting the same respectively are resiliently arranged.

13 designates a feeding or supply nozzle for the mass. which has to becast, and is arranged in such a way in relation to the moulds that during the moments the box or moulds respectively are stationary. one mould is immediately below the said nozzle and can therefore be filled with mass pouring out of the same. The nozzle 13 is provided with a shutting-oft device suitable for the purpose, e. g. a tap 14. by means of which the influx or the flow of the molten mass can be regulated so as to correspond to the capacity of the apparatus.

At the feed-point the lower ends of the tubes 4 are closed by means of suitable shut- 8 provided with ratchet teeth T ting-off devices and arrangements, e. g. a sheet 15, which by means of springs 16 is kept pressed against the bottom of the box. During the rotary motion of the box which is taking place step by step, the material in question is filled into one tube after the other, and the filled tubes are kept cool by a cooling fluid, which is supplied through the tube 28 and discharged through the tube 29, so that the infused mass or material congeals, and in so doing, in the manner stated hereabove, during the congealing process on account of its contraction loosens from the moulds. The congealed bar or stick is ejected from the moulds by means of an ejector-device arranged at an appropriate angular distance from the filling-point in the direction of rotation and consisting of a pin or ejecting member 17 movable up and down, and arranged in such a way in relation to the tubes, that a mould for every step of the rotation of the box is brought right under the centre of the said ejector, which enters the tube or mould and from the same throws out or ejects the congealed bar, which passes out through the lower mouth of the tube and drops into a groove or gutter 30 and slides down either direct into its package or possibly on to a work-table, depending upon which, from a labour point of View, may be found most suitable for the moment.

The ejector is attached to a bracket or a cross-piece 18, which is provided with two downwardly passing guide-bars 19, 20, which are given due and suitable guidance in the stand 1. One of the bars, 20, is provided with a lug 21 and surrounded by a screwshaped spiral spring 22, which with its one end rests against the said lug and with its other end abuts on a cross-beam 33 in the stand. The spring 22 thus depresses the ejector 17 downwardly. By the action of a cam 23, attached to one end of the shaft 9, the ejector is raised upwardly during the rotation of the shaft in the direction indicated by the arrow, inasmuch as a projection 24 on the part 18 abuts on to the circumference of the said cam. When the cam 23 has been rotated far enough for the projection 2a to snap down past the projection 25 on the cam 23, a mould is just in the centre below the ejector 17, which then through the action of the spring 22 enters the mould and ejects the bar. Immediately in front of the ejector, reckoned in the direction of rotation, there is located a knife or like cutting-off device 26 for the purpose of cutting off the tops of of the bars projecting beyond the ends of the tubes, so that the upper ends of the moulded bars are cut level with the upper ends of the moulds. The knife, as will be seen from the drawings, is supported by a clamp-shaped portion 27 For practical use although moulds of perfectly uniform cross section may be employed,

this necessitates very smooth surfaces which in practice it may be diflicult to obtain. In order to counteract the actions of any possible inequalities in the wall-surfaces, the moulds should, preferably as indicated above, be given section that is slightly enlarged downwards.

An apparatus constructed according to the above description enables the casting of bars in moulds undivided lengthwise in a contlnuous manner and the manufacture of a uni form product from a view-point of size and weight, which can, without any risk of breaking, be removed from the moulds, it also eliminates the need of human labour.

The moulds can be made of any suitable heat conducting material.

It should be obvious that the apparatus illustrated here by way of example can be altered without departing from the idea of the invention. Both the propelling device for the cooling-box and the device for imparting to the ejector-device an up-anddownward motion can naturally be carried out in many ways. The plate 15 serving as a shutting-off device can for instance be kept pressed against the lower end of the moulds, e. g. by means of weighted levers or such like, instead of springs.

Having thus described my invention I declare that what I claim is:

The method of making barsfrom a molten material which is exceedingly brittle and friable Without breaking or crumbling the bar before finishing same, comprising pouring the molten material vertically into tubular molds closed and conically expanded at their lower ends, cooling the molds sufliciently to prevent heat expansion thereof from the hot molten mass, cutting the top off the solidified material level with the upper mouth of the mold, and forcing the solidified material downwardly out of the mold by pressure applied to the top of the material.

In testimony whereof I aflix my signature.

STEN FREDRIK VALDEMAR KJELLGREN. 

